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    <meta charset="UTF-8">
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    <title>Document</title>
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<body>
    <script>
        // 训练1
        console.log(`第一题`);
        let a, b, c, d;
        a = 26, b = 17, c = 10, d = 20;
        if (a < b && a < c && a < d) {
            console.log(`a为最小值`);
        } else if (b < a && b < c && b < d) {
            console.log(`b为最小值`);
        } else if (c < a && c < b && c < d) {
            console.log(`c为最小值`);
        } else {
            console.log(`d为最小值`);
        }
        // 训练2
        console.log(`第二题`);
        let API = 56;
        if (API >= 0 && API <= 100) {
            console.log(`空气质量良好`)
        } else if (API >= 101 && API <= 200) {
            console.log(`空气质量轻度污染`)
        } else if (API >= 201 && API <= 300) {
            console.log(`空气质量中度污染`)
        } else if (API > 300) {
            console.log(`空气质量重度污染`)
        }
        // 训练3
        console.log(`第三题`);
        let month = 12;
        switch (month) {
            case 1:
                console.log(`1月`);
                break;
            case 2:
                console.log(`2月`);
                break;
            case 3:
                console.log(`3月`);
                break;
            case 4:
                console.log(`4月`);
                break;
            case 5:
                console.log(`5月`);
                break;
            case 6:
                console.log(`6月`);
                break;
            case 7:
                console.log(`7月`);
                break;
            case 8:
                console.log(`8月`);
                break;
            case 9:
                console.log(`9月`);
                break;
            case 10:
                console.log(`10月`);
                break;
            case 11:
                console.log(`11月`);
                break;
            case 12:
                console.log(`12月`);
                break;
            default:
                console.log(`当前月份不存在`);
                break
        }
    </script>
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